[tzs]

I'm not familiar with the various dishes that were tested. Are any of them dishes that lose mass over time? When I cook rice I've noticed that it weighs quite a bit more shortly after it comes out of the rice cooker than it does a half hour later.

In the article they were weighing at their office. For an in-person order the time between the food being made and the weighing would be the time to get back from the restaurant to the office.

For a delivery order the time from being made to the weighing would be the time it takes the delivery driver to pick up the order plus the time it takes them to get to your office and deliver it.

Unless the driver is already waiting at the restaurant when the food is done, and doesn't wait for other orders to finish too so as to take them at the same time, and yours is the first or only order to be delivered on that run your delivery food on average is going to have been out of the kitchen longer than your in-person ordered food.

[eldaisfish]

If food is sealed or covered, the loss of water should not be significant. What other ways are there for food to lose mass?